regulation of neurotransmitter levels, succinate metabolic process, glutamate metabolic process, glutamate catabolic process, glutamate decarboxylation to succinate, cell-cell signaling, synaptic transmission, cellular amino acid catabolic process, glutamine family amino acid metabolic process, glutamine family amino acid catabolic process, amine catabolic process, organic acid catabolic process, protein-cofactor linkage, transmission of nerve impulse, neurotransmitter metabolic process, neurotransmitter biosynthetic process, dicarboxylic acid metabolic process, carboxylic acid catabolic process, neurological system process,
[Isoform 1]: Expressed in brain. ; [Isoform 3]: Expressed in pancreatic islets, testis, adrenal cortex, and perhaps other endocrine tissues, but not in brain.